Semiconductor switching device

Abstract

A semiconductor switching device includes two FETs with different device characteristics, a common input terminal, and two output terminals. The gate width of each FET is about 400 μm, and the maximum power required for the device operation is maintained by a lager conductivity of the channel layer of one FET and by a lower conductivity of the channel layer of another FET. The device operates at frequencies of 2.4 GHz or higher without use of shunt FET.

Description

BACKGROUND OF THE INVENTION[0001]1. Field of the Invention[0002]The invention relates to a semiconductor switching device for switching at high frequencies, especially to a compound semiconductor switching device operating at frequencies equal to or higher than 2.4 GHz.[0003]2. Description of the Related Art[0004]Mobile communication devices such as mobile telephones often utilize microwaves in the GHz range, and commonly need switching devices for high frequency signals which are used in switching circuits for changing antennas and switching circuits for transmitting and receiving such signals. A typical example of such a switching device can be found in Japanese Laid-Open Patent Application No. Hei 9-181642. Such a device often uses a field-effect transistor (called FET hereinafter) formed on a gallium arsenide (GaAs) substrate, as this material is suitable for use at high frequencies, and developments have been made in forming a monolithic microwave integrated circuit (MMIC) by i...

AI Technical Summary

Benefits of technology

This patent describes a semiconductor switching device that includes two field effect transistors with different saturation currents. The transistors have a common input and output terminals, and control signals are applied to the gates to selectively open or close one of the transistors. The transistor with the higher saturation current has a higher pinch-off voltage, which allows it to handle a higher level of power. The transistors may have different impurity concentrations or depths, and the device may include a semi-insulating GaAs substrate. The transistors may form Schottky contacts with the channel layer and ohmic contacts with the channel layer. The technical effect of this invention is a more efficient and reliable semiconductor switching device that can handle higher power levels.

Problems solved by technology

However, further reduction of the gate width results in a reduction of the maximum power allowed to pass through the switching device.

This maximum power is not enough to transmit signals when the switching device is used in a system conforming to the BLUETOOTH or Wireless LAN standard.

Images